Hi, I am the new owner of a pristine BeoGram 5000, the trouble is that one channel has no sound. I am pretty sure it is the Muting Circuit. I have done the test with the cartridge out and in "play" mode, taking a strand of copper wire and putting it into cart holes, --I only get a hum on two of the holes (I should get hum on all four if the TT is putting out 2 channels). I have verified continuity on the DIN/RCA adaptor. I have looked at the stylus under a microscope, it is in great shape. So I think those are fine. Is there a way to bypass or clean/recondition the muting circuit switch? There are some old posts in the archives on this issue but all seem to be inconclusive, and don't describe a fix. I really want to bring this gem back to life--Thanks for any suggestions or advice!